KR100381035B1 - Nozzle for blow moulding plastic containers and installation provided with same - Google Patents

Abstract

A blow molding apparatus and a nozzle operable to provide fluid into an interior of a blank. The blank is supported in a mold such that a neck of the blank emerges from a wall of the mold. The nozzle includes a nozzle tip and an opening that surrounds the neck of the blank. A peripheral edge of the opening comes to rest on the mold and a seal is provided between the opening and the mold. In one embodiment, the seal is held on the nozzle by a locking ring.

Description

Blow Molding Nozzles in Plastic Containers and Equipment with Nozzles {NOZZLE FOR BLOW MOULDING PLASTIC CONTAINERS AND INSTALLATION PROVIDED WITH SAME}

It is well known to make plastic containers by blow molding plastic preforms.

When the preform is in the parison state, the parison can be obtained by injecting the plastic into the injection molding mold or by extruding the plastic into the molding mold. The parison is then heat-treated appropriately according to the characteristics of the container to be obtained and placed in a final mold having a cavity consistent with the appearance of the container to be obtained. The injection molding nozzle is inserted into the opening of the parison and the blowing fluid, such as air under high pressure, is injected into the parison to expand it, so that the outer surface of the parison is pressurized to the inner wall of the mold cavity so as to press the final container. Get it. In the Applicant's manufacturing machine for making containers from pre-injected parisons, the blowing process was performed by stretching (or stretching) the parison using an elongate drawing rod. In addition, when the stretching process is performed by blowing high pressure air, it is preferable that a pre-blowing step using low pressure air is performed to prevent a large force from being applied to the parison's wall by the rod during the stretching process.

When the preform is in the intermediate container, the intermediate container is generally obtained from the first container obtained by blow molding the parison in the first mold. The first vessel is specially treated, such as heat treatment, after it has been separated from the first mold, thereby obtaining an intermediate vessel, which is placed in the second mold. In this second mold the intermediate container is converted to the final container by blowing the fluid using the same nozzle as mentioned above.

In Applicants' European Patent Nos. 0 237 459 and 0 442 836, two different types of apparatus are obtained, i.e. an apparatus for obtaining a first vessel from an injection molded parison and an intermediate vessel from the first vessel. In particular, a device for obtaining a final container having good mechanical properties in the process of injecting a hot beverage or a carbonated beverage is described.

Typically, the method and apparatus of the second type mentioned above require a conversion through the step of obtaining a single intermediate container. It can be easily expected that a number of intermediate containers must be obtained in series before the final container is obtained.

The mold used to make the final container, or the container making mold from which the intermediate container is made, is generally divided into at least two parts that are joined and separated from each other. Each part is provided with the cavity half part which forms the shape (bottom, main body outer wall, bottleneck part) of the container to obtain.

However, molds consisting of three parts have been known. One part is a mold having a cavity in which the bottom of the container can be molded, and the other two parts are molds capable of molding the body and the bottleneck of the container. In such a configuration, the mold can be easily demolded when the bottom of the container has an uneven shape (especially the shape of the bottom having petals).

These mold portions are inserted from the counterpart when the preform is inserted and the container is demolded. During the blowing step (regardless of the stretching step or the preblowing step) they are combined to close the mold.

One drawback of an apparatus or manufacturer for the production of a container, which may be an intermediate container or a final container, lies in the structure of the blow molding nozzles used in such devices.

The neck portion of the final container is generally known to be obtained during the manufacture of the parison.

When the parison is converted to a container, ie a final container or an intermediate container, the diameter of the neck portion should not be changed, but only a small change, if any. Likewise, the diameter of the neck portion of the intermediate vessel should not change or hardly change, so in all cases the final vessel shall have the same neck portion as the neck portion of the parison. The reason is that the neck portion should have a spiral to allow the spiral cap to be coupled or a reinforcement edge to which the shrinkable cap can be coupled. Therefore, it is very difficult to monitor the deformation of the neck portion after molding the parison or to allow the neck portion to remain intact even after the parison has undergone continuous deformation correction.

During the conversion from the parison to the final container or intermediate container, or from the intermediate container to another container (other intermediate container or final container), the neck portion is supported on the outside of the mold and is not deformed by blow molding. shall.

The nozzle is composed of a tube, and its blowing end (nozzle tip) is narrowed so that it can be inserted through the opening of the preform, that is, the neck portion. Typically, the end of the nozzle is in the form of a truncated cone in cross section. The base diameter of the truncated cone portion forming the nozzle is smaller than the diameter of the opening. Therefore, when the nozzle is inserted into the neck portion, contact is made between the nozzle in the form of a truncated cone and the inner circumferential portion of the neck portion of the preform, so as to form a sealed seal upon injection and to maintain the preform in the correct position with respect to the mold. do.

However, this type of nozzle is not suitable for the following reasons.

-High pressure (typically around 40 bar for the Applicant's dispenser) is required for blow molding, so a large support pressure must be applied between the nozzle and the preform to prevent leakage. Therefore, the neck portion should be thick in order to give sufficient strength so that it does not deform even when the nozzle is pressed. Usually, the manufacturing cost of a container is directly connected to the cost of a material. Previously, in order to reduce the manufacturing cost, the neck portion tended to produce a preform that is not so thick, but the thickness of the neck portion is below the limit at which the nozzle starts to deform the neck portion.

The same apparatus is used to make several different types of containers. The user may change these devices at the request of the orderer. If the height of the neck portion is changed or the diameter of the neck portion is changed, the user changes the movement path of the nozzle or completely changes the nozzle itself. This work takes a lot of time and the cost of equipment is rising.

-These nozzles are not suitable for blowing sterilized or sterile containers for infiltrating sterilized or sterile fluids because the contact of the nozzles with the inner circumferential part of the neck if not sterilized or sterilized before blowing Areas of decay or unsanitary material may remain and contaminate the interior of the container.

If a standard drawing rod is used, the rod is formed in the nozzle and acts axially along the interior of the cylindrical orifice extending along its longitudinal axis and the annular space remains around the rod. This orifice allows the blowing fluid to pass around the rod. However, the cross-sectional size of such annular space is limited to a small rate and the fluid passage speed is slow.

The present invention relates to an apparatus for the production of a container such as a bottle made of plastic, and more particularly to a blow molding of a preform, such as a parison or intermediate container, which is a molten preform obtained in the predeformation stage of the plastic. A blow molding nozzle for a plastic container and an apparatus provided with the nozzle.

1 is a cross-sectional view showing a part of an apparatus using the nozzle of the first embodiment when the nozzle is not in the blown position;

Fig. 2 is a sectional view showing a part of an apparatus using the nozzle of the first embodiment when the nozzle is in the blown position.

Fig. 3 is a schematic plan view showing that the mold in which the nozzle of the first embodiment is used is in a closed state.

Fig. 4 is a sectional view showing a part of an apparatus using the nozzle of the second embodiment when the nozzle is not in the blown position.

Fig. 5 is a sectional view showing a part of an apparatus using the nozzle of the second embodiment when the nozzle is in the blown position.

Fig. 6 is a schematic plan view showing that the mold in which the nozzle of the second embodiment is used is in a closed state.

It is an object of the present invention to overcome these drawbacks of the prior art.

According to the present invention, a blow molding nozzle having an orifice for conveying a fluid to a preform for injecting a blowing fluid into a preform in which a neck portion protrudes from the blow molding mold and a lower side of the neck portion is supported in the blow molding mold is provided. When the preform is placed in the mold and the nozzle is in the blown position, the orifice covers the neck, the peripheral edge of the orifice facing the preform and constituting the tip of the nozzle is in contact with the mold, and a sealing means is provided in this contact area. It is characterized by.

The nozzle according to the invention thus makes it possible to solve all the above mentioned problems.

A relatively thin neck can be used since the nozzle is not in direct contact with the parison to ensure a tight seal.

-The problem related to the orderer's request is solved. Simply select an orifice of a size that can accommodate the largest neck portion that will be processed by the machine.

-Since the blown fluid reaches the circumference of the neck part, problems related to aseptic or sterilization treatment are solved. In addition, since the blowing fluid reaches the circumference of the neck portion, not only the inside of the container but also the outside of the neck portion can be cleaned.

-Although the drawing rod is used, the injection end of the blowing fluid is large and the blowing efficiency is good because the nozzle tip is not inside the neck part but outside the neck part.

In the first embodiment of the present invention, the sealing means is fixed to the tip end of the nozzle.

In a second embodiment, the closure means is fixed to the mold of the device in which the nozzle is used.

Referring to the present invention in more detail based on the accompanying drawings as follows.

1 and 2 show a nozzle of a first embodiment according to the present invention and a part of a blow molding apparatus in which such a nozzle is used.

The nozzle 1 is in the form of a cylindrical sleeve and has a shaft hole composed of two orifices 3 and 4 coaxial with the axis 5 of the nozzle along its entire length and in communication with each other at the first end side. to be.

According to the invention, among these orifices, the first orifice 3 constitutes a passage for transferring fluid to the preform side when the nozzle is placed in the blow molding apparatus as will be described in detail later.

In the embodiment shown in FIGS. 1 and 2, the sealing piece 6 is fixed around the second end of the first orifice 3 and extends in the axial direction to substantially constitute the tip 7 of the nozzle. The function of this sealing piece 6 is to allow the sealing to be made during blowing, as will be described in detail later. The sealing piece 6 is formed around the end of the first orifice 3 formed in the nozzle body 2 by a fixing ring 8 which is helically coupled around the second end of the first orifice 3, for example. It is fixed.

The through holes 9 and 10 are formed radially through the fixing ring 8. The function of these through holes is described in detail later. These through holes are arranged at regular intervals around the fixing ring 8 and have a contact plane between the nozzle body 2 and the opposite ends of the sealing piece 6 substantially constituting the nozzle tip 7 at the inner side thereof. 11) It is open to the side.

As is well known, the nozzle 1 is fixed at both ends with respect to an end where the first orifice 3 is formed and a nozzle ram 12 for operating the nozzle. In particular, the fuselage 2 is fixed to a spindle 13 coupled to a piston 14 operating in a cylinder 15, the assembly of pistons / cylinders / spindles making up the ram.

As shown in FIGS. 1 and 2, the cylinder 2 of the nozzle is helically coupled to the end of the spindle 13. To this end, a spiral is formed on the second orifice 4 formed on the body 2 and a spiral is formed on the end of the spindle 13.

The ram is a double acting ram. To this end, the first orifice 16 formed at one end of the cylinder 15 allows the piston and the nozzle 1 coupled thereto to be moved toward the mold 17, and the second orifice 18 allows the nozzle to be molded. It can be moved away from.

As is well known, an assembly consisting of a piston 14 and a spindle 13 extending therefrom has a tubular orifice 19 coaxial to the axis of symmetry 5 of the nozzle 1 and the ram 12 along its entire length. ) Is pierced.

A rod 20 for stretching the preform 21 is disposed in this orifice. The inner diameter of the orifice 19 is larger than the outer diameter of the rod 20 so that an annular space 22 is formed around the rod 20 so that the pre-blown or blowing fluid passes through the first orifice 3 of the nozzle 1. It is directed toward the preform 21 so that the required container in the mold 17 can be manufactured.

The annular space 22 is arranged in communication with the pipe 23 for conveying the pressure fluid for pre-blowing or blowing. This pipe 23 is connected to one or more fluid sources as is well known.

The rod 20 may act on the assembly of the cylinder 15 on the one hand and the assembly of the piston 14 / spindle 13 / nozzle 1 on the other hand. The means for moving the rods are well known and therefore not shown. These may be ram, cam and follower mechanisms or other suitable means.

As is well known, bearings 24 and 25 for guiding the rod 20 are provided between the ends of the cylinder 15 and the connection between the spindle 13 and the nozzle 1, respectively. Furthermore, at the end of the cylinder the guide means are closed. To this end, the bearing 24 is a hermetic bearing or a form in which the seal 26 is supplementally coupled.

The purpose of sealing this part is to prevent the blowing fluid from leaking through the circumference of the rod 20.

A bearing 25 guiding the rod at the connection between the spindle 13 and the nozzle 1 is inserted into a request 27 formed at the end of the spindle 13, for example when mounted on the spindle 13, to the nozzle. It is composed of a ring fixed by. In addition, at least two orifices 28 and 29 are formed in the ring through its entire height, and each of them is in communication with the annular space 22 and the first orifice 3 of the nozzle 1, so that the blowing fluid From the pipe 23 which conveys this blowing fluid, it can flow to the front-end | tip part side of a nozzle.

Of course, the nozzles can be fitted by fitting the nozzle 1 to the spindle 13 or by using attachment means such as seals or other known devices (sealing strips, joint compounds, sealing hemp fibers, etc.). It is fixed to the airtight seal).

In FIG. 1, the nozzle 1 and the drawing rod 20 are shown to be in an elevated position (when the mold is disposed below the nozzle). Thus, the nozzle is far from the preform 21 and the rod 20 is retracted to the nozzle side.

In the case of the parison, the preform 21 is placed in a mold 17 having a cavity 30 which forms the shape of the container to be obtained.

In Fig. 2, the nozzle is in a blown state. The tip 7 of the nozzle, in particular the sealing piece 6 constituting it, is in contact with the upper edge 31 of the mold, and the rod 20 begins to draw the bottom of the parison, i.e. the parison. It is shown to be in a position to.

In this figure, the first orifice 3 of the nozzle 1 is sized such that the neck portion 32 of the preform 21 can be sufficiently covered by this orifice and accommodated.

As is well known, the upper edge 31 of the mold 17 to which the sealing piece 6 is pressed is two half-rings facing away from the connecting line 35 of the two half-moulds 36 and 37. It is a ring consisting of (33) and (34). This ring is a replaceable part.

The through-holes 9 and 10 formed near the tip 7 of the nozzle release some of the pressure fluid still remaining when the nozzle is moved upward from the mold after blowing, so that the sealing piece 6 is damaged. It is to prevent. Without these openings, the sealing piece 7 will tend to outward when the nozzle starts moving upwards due to the high pressure remaining in the nozzle.

By this opening, the sealing piece is opened at the moment when the nozzle starts to move upward from the mold 17, and it is prevented from coming into close contact with the half-rings 33 and 34.

In particular, due to the internal pressure, the inner circumferential surface of the sealing piece tends to move in a direction away from the region in which the sealing piece is in close contact with the nozzle body 2, whereby a gap is formed between the sealing piece and the nozzle body, so that some fluid passes through And outward through this gap. Figures 4 and 5 show another embodiment of the nozzle. Fig. 6 shows that the mold needs to be adapted to this other embodiment. The nozzle of this embodiment is simply the means used to enable a seal between the tip 7 of the nozzle and the mold. It is different from the means of FIG. Therefore, the same parts as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be referred to those described with reference to FIGS. 1 and 2. In the orifice, the first orifice 3 is sized to sufficiently wrap the neck portion 38 of the preform 39. In this case, the preform It is an intermediate container having a narrow body as shown in the Applicant's European Patent No. 0 442 836. The spirally formed second orifice 4 is helically coupled to the spiral portion of the spindle 13 connected to the piston 14. The drawing rod 20 moves in the ram 12. The difference between these nozzles and the nozzles shown in Figs. 1 and 2 is the first of which the tip 7 of the nozzle does not consist of a seal and is directed outward. Rim of the opening of the orifice (3) And the first orifice completely penetrates the body 2. The top walls 44, 45 of each half-mould 46, 47 when the nozzles are placed in use (FIG. 5). Two semi-circular seeds disposed in each of the neck rings, consisting of two half-rings 48 and 49 disposed on each half-mold, or in the case of a neck ring (FIG. 6). Sealing is achieved by a seal 41 consisting of portions 42 and 943. One advantage of this embodiment is that the seal can be placed stably and does not open out when the nozzle is raised. It was found that the nozzle accordingly did not need to strongly adhere the preforms 21 and 39 against the mold in the neck ring during blowing. Therefore, the container can be manufactured without using the drawing rod 20 for fixing the preform to the mold. Even when the rod is not used, the preform is not vibrated by the effect of the fluid and the fluid is not discharged to the mold side through the outer circumference of the preform. The fluid is directed to the interior of the preform without any particular problem.

The invention is not limited to the illustrated embodiments. In particular, the nozzle is not fixed by the spirally formed orifice 4 and the spiral formed on the spindle 13 of the ram, but may be fixed to the ram by other means. Similarly, the drawing rod 2 may not be necessary. This is nothing more than a nozzle or an accessory to the device in which it is used.

Claims (13)

Preforms 21 and 39 supported by the lower side of the neck portion in the blow molding mold such that the neck portions 32 and 38 protrude from one wall 31; 44, 45 of the blow molding molds 36, 37: 46, 47. In a blow molding nozzle 1 having an orifice 3 for conveying a fluid to a preform for injecting a blowing fluid into the nozzle, when the preform is placed in the mold and the nozzle 1 is in the blowing position, the orifice is necked. The peripheral edges 6 and 40 of the orifices covering the part and facing the preform and constituting the tip 7 of the nozzle are in contact with the walls 31; 44 and 45 of the mold, and the sealing means 6 in this contact area. : 42, 43) nozzles for blow molding plastic containers. 2. The nozzle according to claim 1, wherein the sealing means consists of a sealing piece (6) surrounding the tip portion (7) of the nozzle. 3. The nozzle according to claim 2, wherein the sealing piece is fixed to one end of the body (2) of the nozzle by a fixing ring (8). 4. A nozzle according to claim 3, characterized in that the retaining ring is screwed around the end of the body (2). 5. The method according to claim 3, wherein the retaining ring has one or more through holes (9, 10) open in the contact plane (11) through which the sealing piece (6) contacts the end of the body (2). 6. Nozzle characterized in that. Preforms 21 and 39 supported by the lower side of the neck portion in the blow molding mold such that the neck portions 32 and 38 protrude from one wall 31; 44, 45 of the blow molding molds 36, 37: 46, 47. Apparatus for blow molding a container from a preform consisting of a blow molding nozzle (1) having an orifice (3) for conveying fluid to the preform for injecting a blown fluid into the mold, wherein the preform is in a mold. When placed and the nozzle 1 is in the blown position, the orifice 3 covers the neck and faces the preform and the peripheral edges 6 and 40 of the orifice constituting the tip 7 of the nozzle are said walls of the mold. And a nozzle (1) in contact with (31; 44, 45) and provided with a sealing means (6: 42, 43) in this contact area. Preforms 21 and 39 supported by the lower side of the neck portion in the blow molding mold such that the neck portions 32 and 38 protrude from one wall 31; 44, 45 of the blow molding molds 36, 37: 46, 47. An apparatus for blow-molding a container from a preform consisting of a blow-molding nozzle (1) having an orifice (3) (4) for conveying fluid to the preform for injecting a blown fluid into the preform, the apparatus comprising: a preform When the nozzle 1 is placed in the mold and the nozzle 1 is in the blown position, the peripheral edge 6 of the orifice 6 covers the neck portion, faces the preform, and constitutes the tip 7 of the nozzle 6; Is composed of the nozzle 1 in contact with the walls 31; 44, 45 of the mold, and in which the contact area is provided with sealing means 6: 42, 43, the sealing means 42, 43 being necked. The seals 41, which are supported by the walls of the mold on which the parts 32, 38 protrude, surround the neck part, are constructed. In blow-molding apparatus of a plastic container, characterized by. 8. Apparatus according to claim 7, characterized in that the mold consists of two half-molds (46; 47) and the seal consists of two seal portions (42; 43) disposed in each half-mold. Device according to claim 7, characterized in that the first orifice (3) of the nozzle is arranged in communication with the pipe (23) for transporting the fluid. 10. The device of claim 9, wherein the nozzle is coupled to and in communication with the ram (12) of the device. Device according to claim 7, characterized in that a rod (20) is configured for extending through the first orifice (3) and being able to act in the orifice to draw the preform (21; 39). 11. The nozzle (1) according to claim 10, characterized in that the nozzle (1) is fixed to the spindle (13) of the ram (12), which spindle is fixed to the piston (14) acting in the cylinder (15) configured in the device. Device. 13. Device according to claim 12, characterized in that the nozzle (1) is fixed to the spindle (13) by the combination of the spiral of the second orifice (4) and the spiral formed on the spindle (13).